Waterhead Ratings
A waterhead rating, also known as hydrostatic head, or HH, measures how waterproof a tent’s fabric is. The number (e.g. 1500 mm) refers to how tall a column of water the fabric can support before it leaks.
It applies only to the fabric, not seams, zippers or design. The real-world waterproof performance depends on the full tent construction, not just the spec.
Rating Categories & What They Mean
- 0–1000 mm = water-resistant only; suitable for light showers, typically 2-season tents
- 1000–1500 mm = entry-level waterproof; common in lightweight 3-season hiking tents
- 1500–5000 mm = very waterproof; ideal for family or 3–4 season tents used in extended wet conditions
- 5000 mm+ = highly waterproof; built for extreme use or prolonged rain, though often heavier and stiffer fabrics
Tent Floors Need a Higher Rating
Tent floors should have a higher waterhead rating than the outer flysheet. Floors endure body pressure and ground moisture, so a typical hiking tent floor needs around 6000–10,000 mm, while many family-style tents use PVC or polyethylene floors, which perform differently and often lack separate HH ratings.
Higher Numbers Aren’t Always Better
Ultra-high HH coatings can make materials heavy, stiff and prone to delamination or weakened tear strength. A well-designed tent with moderate HH but sealed seams and smart design often outperforms one with a very high spec but poor craftsmanship.
Care & Maintenance Tips
You can't raise your fabric’s inherent HH rating, but you can improve overall waterproofing:
- Apply seam sealers to stop leaks at stitch lines
- Reapply Durable Water-Repellent (DWR) spray to help water bead off rather than soak in
- Use a groundsheet or tarp for added protection
- Store and pitch the tent properly to reduce wear on coatings and seams
Choosing the Right Rating for Your Needs
- For summer or dry-weather camping, 1000–1500 mm is usually sufficient
- For year-round or wet weather, aim for 1500–3000 mm on the fly
- For frequent or expedition-style use, a 3000–5000 mm fly and a 6000–10 000 mm floor rating is more reliable
Quick Summary:
- 0–1000 mm = water-resistant
- 1000–1500 mm = waterproof
- 1500–5000 mm = very waterproof
- 5000 mm+ = extreme waterproof
- Floor rating ideally 2× fly rating for robust protection